Working group II (WGII) « Hazard and Disaster Risk ......Working group II (WGII) « Hazard and...

Working group II (WGII) « Hazard and

Disaster Risk Management in Mountain

areas » of the Working Party on the

Management of Mountain Watersheds

(WPMMW) of the European Forestry

Commission (EFC).

Workshop 1 – Hazard zone mapping and the integration of the forest

protection function

Synthesis of discussions

15 - 17 October 2014

Redactors:

Alison Evans (ONF RTM France – Haute Savoie)

Benjamin Lange (Swiss Confederation – Federal office for the environment – Division risk prevention)

Jérôme Lievois (ONF RTM France– Haute Savoie)

Margarete Wöhrer-Alge (Austrian Service for Torrent and Avalanche Control – Vorarlberg)

Musa Kaya (OGM Turkey)

Pierpaolo Macconi (Autonomous Province of Bozen – Italy)

Quentin Delvienne (ONF International France)

Rudolf Schmidt (Austrian Service for Torrent and Avalanche Control – Vorarlberg)

Sıtkı Eraydın (OGM Turkey)

Wolfgang Gasperl (Austrian Service for Torrent and Avalanche Control – Oberösterreich)

Reviewers:

Catrin Promper (FAO)

2

Table of contents

I. Introduction and Objectives of the workshop ................................................................................................ 3

II. Overview of country approaches .................................................................................................................... 3

Hazard zone mapping ......................................................................................................................................... 3

Consideration of the forest protection role during HZM ................................................................................... 4

III. Discussion .................................................................................................................................................. 7

Institutional and legal framework ....................................................................................................................... 7

Evolution of instruments for assessment of forest protection function ............................................................. 8

Influence of HZM on the forest management..................................................................................................... 8

Technical structures Vs protection forest / revision of HZM .............................................................................. 9

Awareness raising of national and local politicians, law makers and forest owners .......................................... 9

IV. Conclusion ................................................................................................................................................ 10

V. Annexes ......................................................................................................................................................... 11

3

I. Introduction and Objectives of the workshop

The first workshop of the Working group II (WGII) « Hazard and Disaster Risk Management in Mountain areas »

of the Working Party on the Management of Mountain Watersheds (WPMMW) of the European Forestry

Commission (EFC) took place in the municipality of Sixt Fer-à-Cheval in the department of Haute-Savoie

(France), in October 2014.

The aim of the workshop was to exchange experiences, practices and ideas between practitioners about hazard

zone mapping and the integration of the forest role and to report lessons learned and interesting ideas of

practitioners for improvement of policies and processes at national and provincial levels (Refer to annex 1 for

detailed Terms of Reference of the workshop).

Austria1, France2, Italy3, Turkey4 and Switzerland5 participated in a three day workshop divided in two main

parts. The first part was dedicated to presentations of country participants (refer to annex 2, 3, 4, 5, 6 for

country/province presentations respectively for Austria, France, Italy, Turkey and Switzerland), the second part

was dedicated to visits and discussions on specific field cases.

The participants of the workshop made a debriefing at the end of the exercise and decided according the ToRs

to establish a synthesis report with the aim of emphasising key findings and important points that could be

taken into account to reinforce the hazard zone mapping process and the integration of the protection function

of the forest.

II. Overview of country approaches

Hazard zone mapping 6

Except Turkey which is under development of its global framework for hazard zone mapping, the other

participating countries/province have developed strong institutional and legal frameworks and experienced

hazard zone mapping with incidence for land use planning.

First experiences of hazard zone mapping (HZM) took place in the fifties (Switzerland), seventies (Austria,) and

eighties (France) accordingly with new legislations/regulations about natural risk management.

Autonomous Province of Bolzano built its HZM system in 2008 and managed to adapt best concepts and

methods used in other countries to its own context which is a very interesting case.

In each country/province, the institutional and legal framework is different and plays an important role in the

efficiency of the implementation of HZM. The approach for hazard zone mapping is either a top down approach

(centralised) or a bottom up approach (decentralized).

Methodological approaches are also different even though general concepts are similar. HZM is mainly based

on the knowledge of past events that remind us the importance of event documentation and the study and

modelling of potential hazards. Risk maps are integrated/used in land use planning and contingency plans.

1 Federal Ministry of Agriculture, Forestry, Environment and Water Management. Service for Torrent and Avalanche Control 2 National Forest Office – Service of Mountain natural risks management (ONF RTM) 3 Autonomous Province of Bolzano – service of torrent and avalanche control 4 OGM – General Direction of Forestry – department of soils conservation and watershed rehabilitation 5 Swiss Confederation – Federal office for the environment – Division risk prevention 6 For more detailed information, please refer to annex 7 which is a synthesis table of the institutional, legal and technical framework of

HZM.

4

The scale of the elaborated maps varies from 1:10.000 to 1:2.000. For maps with a strong implication in land

use planning, it is important to target a small scale in high density areas.

Switzerland and Autonomous Province of Bolzano are systematically using danger levels for mapping according

to a probability-intensity-diagram (5 hazard zone types). The level of probability varies in function of the return

period of the considered hazard. This approach is a good way to standardize the HZM methods at the scale of a

state/province territory and tends more or less to impose quantitative assessment of hazards and protection

works.

Figure 1: Probability-intensity-diagram

Except France, hazard maps/risk maps are upgradable with the construction of protection works or existence of

new forests. In this case, land use plans have also to be reviewed. The possibility of building housing under

protection works is open if the sustainability of the protection is ensured. In France except for particular cases,

this possibility is not yet permitted.

In the past, HZM was based mainly on an expert opinion that today is questioned by the public as

quantification methods have been developed. The technical knowledge to estimate risks is shared through

internet and can be used by people with scientific background. Therefore, critical comments on risk mapping

are increasing. A fact which is linked with the pressure on land in mountain areas for new buildings.

It is a fact that techniques and needs for expertise have evolved and impacted negatively the cost of the

process and positively the accuracy of the data used for land use planning decision making. It should be

therefore interesting to compare the average expertise cost per hectare invested in HZM.

Consideration of the forest protection role during HZM 7

The consideration level of the protection role of the forest in HZM varies from country to country. It shows us

all the complexity of the subject and how it is linked with political will, as a lot of scientific knowledge already

exists.

The protection function of a forest depends obviously on the area it covers, its composition and structure and

the characteristics of the considered hazard.

7 For more detailed information, please refer to annex 8 which is a synthesis table of the consideration of the forest protection role in HZM

for each participating country/province.

5

It is well known and validated at international level and between practitioners that:

mountain forests can play a protection role against rockfalls decreasing the energy of the stones. The

protection role of the forest can be assessed quantitatively with 1D, 2D or 3D models (not the state of

the art) and integrated in HZM if the legislation allows to take it into account;

mountain forests can have a protective function role against avalanches stabilizing the starting zone

(active protection). On the other hand, drifted woods can be transported by avalanches either in their

channels or in torrent or river beds.

In the case of this hazard, the quantification of this protection role can be approached by measuring

the interception area by the tree crown cover;

mountain forests can play a protection role against shallow landslides fixing the soil to bedrock (tree

roots stabilize soil) and preventing soil movement; the quantification of this protection role is not very

well known for the moment and more research on this topic should be launched;

mountain forests can play a positive (watershed runoff) and negative (bridge clogging phenomena)

protection role in the case of torrent floods and debris flows. The quantification of the positive or

negative role is hardly possible;

For practitioners from each participating country/province, the consideration of the protection role of forests

against hazards is not completely the same. Divergence exists in function of the hazard type but in general the

positive effect of the forest is emphasised.

Figure 2: Synthetic table and chart presenting the consideration by participants of the forest protection role for

mentioned hazards (does the forest play a protective role for avalanches (1 answer per participating

institution))

Taking into account positive effects of forest cover (similarly to protection structures) in HZM means taking on

the responsibility to keep this function effective over a long time period. At the moment, the protection

function of the forest is partially taken into account in the hazard zone mapping process.

General consideration of the

protection function of forest

per hazard type

Positive and

negative (50/50)

Both but in general

more negative

Both but in general

more positive Positive

Avalanches 3 2

Debris flow 1 1 3

Rockfalls/rockslides 2 3

Shallow Landslides 4 1

Torrent Floods 1 4 Total number of answers

Total 2 1 16 6 25

% 8 4 64 24

8%4%

64%

24% Positive andnegative

Both but in generalmore negative

Both but in generalmore positive

positive

6

Figure 3: Synthetic table and chart presenting the effective consideration of the protection forest function

during HZM

Austria and France have specific colours in risk maps for protection forest (respectively blue and green

reservation areas) that impose to implement appropriate forest management measures to conserve the

protection function. The effort to map protection forests for this precise function stays unsystematic and

depends mainly on the affinity of the client and/or the experts doing the job.

Autonomous province of Bolzano takes unsystematically the protection forest function into account during

HZM process but maps this as protection works. In this province, the implementation of adapted sylvicultural

measures is not mandatory when the protection forest is mapped and reported in the hazard map.

In Switzerland, for the moment, protection forests are also unsystematically considered in HZM but there are

some efforts to quantify the significance of the protective function of forests keeping in mind the economic

interest to ensure the sustainability of such device (mostly cheaper than building concrete protection works).

Specific forest management standards have to be applied if a forest is officially delimitated as a protection

forest (about 50 % of the forested area in Switzerland), independently of the landowner’s type. Protection

forest management guidelines (2005) have to be applied everywhere. A system of subsidiarity is put in place by

the confederation as there is a loss of earnings for the owner in terms of wood production.

In some cases, hazard assessment tools that can be used for HZM are defined by legislation and there is an

obligation to use the “official” methodology.

Implementation of an assessment

process of the forest protection

function during HZM per hazard

type

Never madeSystematic and

mandatory

Systematic

but not

mandatory

Unsystematic

Avalanches 1 4

Debris flow 1 4




Total 1 2 2 20 25

% 4 8 8 80

4% 8%

8%

80%

Never

Systematic andmandatory

Systematic but notmandatory

Unsystematic

7

Figure 4: Synthetic chart presenting the type of assessment of the forest protection

role during HZM when it is made

Even if the forest protection role is taken into account during HZM, the assessment made is mainly qualitative.

In case of important stakes and dangerous past events, modelling is used to assess the protection role of

forests.

III. Discussion

The following discussion and conclusion is a synthesis of the ideas exchanged between practitioners during the

workshop. Those results are participant opinions and do not necessarily reflect the view of their institutions.

Institutional and legal framework

Institutional frameworks are multifaceted for HZM and the decision making process is organized differently in

each country/province. In some cases, processes are heavy and depend on a lot of legal texts which can be

antagonist and introduce conflict of interest notably at local level.

Especially in countries with a long experience in HZM like Austria and France, the legal framework for HZM is

complex, spreads over a lot of texts because of the evolution and is sometimes inconsistent (gaps). The

necessity of consolidation of the legal framework was identified. But for Austria from a practical point of view

works quite well.

The final decision on the level of a risk with incidence for land use planning should always stay in the hands of

independent expertise/state agency because there is a real conflict of interests if it is the mayor/local

government representative who takes the final decision. This measure is also a necessity to ensure a better

governance at local level.

According to the participants of the workshop, a participative bottom up approach for HZM is more relevant as

it ensures the involvement of local stakeholders, facilitates the appropriation of the plans and increases

Type of assessment of the forest

protection function during HZM

per hazard type when it is made

Generaly qualitative but sometime

quantitative depending on the

stakes

Qualitative

Avalanches 4 1

Debris flow 3 2




Total général 14 10 24

% 58 42

58%42%

Generally qualitativebut sometimesquantitave dependingon the stakes

Qualitative

8

globally the consciousness of the public to take the risk into account in local development and to manage it

properly.

It is evident that identification of protection forests has to be done by the state/local government

independently of the landowner’s type or where the forest stands and that mandatory management measures

to keep the protection function of the forests, have to be applied with the same rules.

Evolution of instruments for assessment of forest protection function

The quantitative and qualitative assessment of the protection role of forests for HZM has progressed rapidly

since 1995. Several models (rockfalls…) exist in 1D, 2D or 3 D and are for some, based on recorded events.

A systematic assessment of the forest protection functions against natural hazards should be considered by

institutions and governments. New technologies, especially remote sensing (LIDAR) combined with GIS, have

reduced drastically the cost and the arduousness of such work. This systematic technical process of protection

forest function identification will highlight that on one hand a few forests considered as having a protection

function in the past do not in fact play a protection function and on the other hand that non-identified

protection forests play an important function for human stakes. Specific forest management and adaptation of

existing protection device should be implemented after this assessment.

The consideration and assessment of the forest protection function is therefore an intellectual, political and

economic responsibility. Ultimately, protection forests should be considered as a part of protective devices and

be managed and monitored like protection works.

From a socio-economic point of view, these changes should be interesting in terms of avoided events and

economic impact (closure of roads threatened by rockfalls due to inadequate cuts in protection forests, for

example). They could also generate benefits in terms of employment and local development (necessity for a

regular and appropriate forest management and mobilization of sawn timber or biomass - local employment

and wood production).

Influence of HZM on the forest management

The identification of protection forests and the consideration of their protection function should be

accompanied by mandatory specific forest management measures. Adapted management measures are

already implemented in some cases but it is still unsystematic. In France, a sylvicultural forest mountain guide

exists but is poorly used due to the fact that it is not mandatory. In Switzerland, a guideline how the influence

of protection forests on natural hazards may be quantified was published in 2015..

Implemented sylvicultural measures in protection forests have generally the aim of sustaining or increasing the

protection function (foster available space to increase natural regeneration, conversion of the forest,

plantation undercover, etc.) and keeping this function at an acceptable level even after actions (secure fallen

trunks with anchors, stems cut at 1,5 meters, etc…, to increase the roughness of the slope).

We should ask ourselves if the mountain protection forests were better managed in the past than nowadays in

terms of the frequency of the cuts and the development of regeneration surfaces or if this is a matter of

increasing land use pressure We notice that protection forests in steep slopes are neglected because of the

technical and economic difficulty to organise cuts, particularly in private plots. The protection function is

decreasing in those plots and we should be prepared to observe new phenomena if nothing is done.

A system of grants for landowners could be put in place like in Switzerland and Austria, to support the

additional costs of a specific forest management aiming to maintain its protective function. In reference to a

previous section of this report, the practitioners believe that such a policy would encourage socio-economic

9

local development and employment. The EU is already funding sylvicultural actions to sustain the protection

function of forests, therefore governments should transform this opportunity. This adapted approach would

also increase the risk culture at local level.

Technical structures Vs protection forest / revision of HZM

For some people, the equivalence in terms of function between a forest protection and a protection structure

(a dam for example) is not clear, although the functional role can be the same. In our territories, forests ensure

this protection function in a lot of places that people even do not know.

This equivalence should be considered only in the case where the quantification of the protection function of

the forest is possible (torrent concentration, rockfalls and starting zone of avalanches…).

In case of exceptional events, the forest can disappear in the same way as protection structures. In this case,

hazard and risk maps should be adapted and wit direct effects to land use planning.

The question of constructing a building or not, below or beside a protection element, should only be

approached considering the functionality and sustainability of the element in its environment.

Awareness raising of national and local politicians, law makers and forest owners

The awareness of the decision makers concerning HZM should be reinforced with the aim of avoiding

undesired legal processes including cases of conflict of interest.

In general, local politicians and stakeholders do not feel comfortable with the HZM processes and procedures,

it is therefore really important to increase their understanding of the whole process and their own role in it:

how a hazard is quantified, what can be the impacts of the underestimation of a phenomenon,…

In a decision making process, because of their independence and their risk culture, practitioners should always

have the possibility to give their opinion if they believe that a taken decision is not adequate and puts citizens

in high danger. In HZM, the role of practitioners is clear and includes technical aspects (diagnosis and

assessment of hazards, possible cost-effective measures, etc.) and communication (communication of risk

management, transfer of knowledge, etc.).

10

IV. Conclusion

The first workshop of WG II of WPMMW involving only practitioners was a success and there is a strong will

between institutions to continue such exchanges in the long term.

During the workshop, the working group developed a lot of ideas and recommend to EFC/countries/provinces

if it is not already done to:

analyze the legal decision making process for HZM and adapt it to avoid gaps and conflict of interests,

to ensure a bottom up approach and to integrate the forest protection function (constraint for every

landowner’s type) correctly;

implement a systematic identification and assessment of protection forests where it is needed, adapt

the forest management in consequence regardless of the landowner type (obligation for public

security – adaptation of policies) and upgrade the protection device if needed;

adapt policies to ensure the technical and economic management of identified protection forests

using specific techniques with an important impact on employment and local development;

consider the equivalence between a forest and a protection work only in the case where the

quantification of the protection function of the forest is possible (torrent concentration, rockfalls and

starting zone of avalanches,…);

make the HZM an easy and continuous upgradable tool for land use planning;

ensure a better communication on HZM to stakeholders and provide practitioners with adequate

pedagogic tools.

The function of the forest to mitigate shallow landslides should be studied further to acquire enough

knowledge to integrate it into HZM.

The socio-economic and environmental impact of protection forests especially in term of avoided costs for

human stakes protection should be better studied to complete the picture and have stronger arguments to

lobby for a better consideration of the protection function of each forest.

11

V. Annexes

Annex 1: Terms of reference of the workshop

Annex 2: Austria presentation

Annex 3: France presentation

Annex 4: Italy, Autonomous province of Bolzano presentation

Annex 5: Turkey presentation

Annex 6: Switzerland presentation

Annex 7: Field visits

Annex 8: Field visit sheet: Sixt-Fer-à-Cheval – Le Giffre – Rockslides near the Fer-à-Cheval

circus)

Annex 9: Field visit sheet: Morzine/La Tassonière; Valley of slates: la Daranse des Prodains;

Rockfall hazard)

Annex 10: Field visit sheet: Morzine/Manche Valley. La Dranse de la Manche. Rockfall

hazard)

Annex 11: Table of the institutional, legal and technical framework of HZM

Annex 1: Terms of reference of the workshop

First workshop of the working group II (WGII) « Hazard and

Disaster Risk Management in Mountain areas » of the

Working Party on the Management of Mountain Watersheds

(WPMMW) of the European Forestry Commission (EFC).

Terms of reference

Facilitation of exchange between practitioners of WPMMW partners on

hazard zone mapping and the integration of the forest role

France

15 – 17 October 2014

Context

The leaders of the WGII designated during the meeting of the WPMMW of 2013 in Montgenèvre, Austria and

France, met on 17 January 2014 for the first time in the framework of the WGII. The activities of the WGII until

the next meeting of the WPMMW were discussed and scheduled.

Subsequently specific terms of reference and the workplan of WGII have been developed for 2014 and 2015.

For this period the general objective of the action is to build capacity of internal staff on the topic of hazard

mapping with a focus on the special role of forest.

For the period 2014 and 2015, 2 workshops are scheduled. The first one will take place in France in autumn

2014 and the second one will take place in Austria during spring 2015.

The aim of the present ToRs is to specify the content and the program of the first workshop. The present ToRs

will be used to present the first activity to other member countries of the WPMMW and involve them in the

implementation of the WGII. It is really important to include other countries at this stage to strengthen WGII

and have a better picture of the European diversity.

General objective:

Build knowledge of practitioners on hazard zone mapping including the consideration of the forest’s protection

role.

Specific objectives:

OS 1: Compare procedures and/or regulations of participating countries that define the consideration of the

forest’s protection role in hazard zone mapping;

OS 2: Compare methodologies and approaches between countries on this topic.

Place

The workshop will take

place in France in the

department of “Haute

Savoie” in the

municipality of Sixt-Fer-

à-Cheval, 70 kilometers

from Geneva, which

allows an easy access

from the international

airport.

Activities

1. Preparation of

the workshop in terms of logistic and material. It will be asked to each participating country

(depending on the number of countries involved) to prepare short presentations of case

studies where the forest protection role has been included in the analysis for hazard

mapping. These slideshows will present different aspects of hazard zone mapping and the

integration of the forest’s protection role at national level (rules, procedures if they exist,

special field cases, etc.). Important issues for the slideshow design and harmonization

between partners will be provided by the organization.

2. Implementation of the workshop. A 3 days program will include a general presentation on

hazard mapping technics presented by the hosting country and small case studies presented

by participating countries (half day = day 1), an entire day dedicated to field visits highlighting

the different roles of forest in risk prevention (positive and negative) and the integration in

hazard mapping (day 2), synthesis of the field visits – recommendations – workshop

evaluation (half day = day 3),

3. Reporting of the workshop. Synthesis of presentations and field visits, analysis of

participant’s recommendations and synthesis of the workshop evaluation.

Attended results

A synthetic report of the workshop which will include:

A synthesis of presentations, field visits and technical exchanges between practitioners;

A synthesis and analysis of main recommendations;

A compilation of interesting topics to address under WGII.

An evaluation of the content and the organization of the first workshop.

Logistics

France provides the organization of the workshop.

A list of accommodation on, or close to the meeting venue, will be provided to all participants.

Each country will cover travel costs, accommodation and meals of its participant

Annex 7: Field visits

This annex presents the content of the field visits of the workshop focusing on the situation of the different

stops and the key subjects that where discussed.

A = idea, point highlighted by an Austria practitioner

B = idea, point highlighted by a practitioner from Bolzano province

CH = idea, point highlighted by an Swiss practitioner

F= idea, point highlighted by an French practitioner

T= idea, point highlighted by an Turkish practitioner

Stop n°1: Sixt Fer-à-cheval. Settlement of Frenalay

(See “Field visit sheet: Sixt-Fer-à-Cheval – Le Giffre – Rockslides near the Fer-à-Cheval circus”. Annex

8)

The situation:

Case of an ageing forest above the small settlement of Frenalay. This forest is private at the foot of the slope and belongs to the municipality on the upper part (see « Field visit sheet » plot n°2 on map). For centuries, this forest has been considered as a protection forest. Wood harvesting is forbidden. Today, the crop is ageing and it is less and less dense. Specific forest management would be needed to launch the rejuvenation of the crop, but as far as the native owners remember, no trees have ever been cut, and they have been protected (they say…). This zone is covered by an old hazard map (1987) that should be revised in the years to come. For the moment the forest, the fields below, and 2 houses at the bottom of the slope, are covered by a moderate hazard zone for rock falls. The risk map allows building in the field between the foot of the forest and the first houses, with appropriate protection structures, but it does not specify any measures for the management of the forest.

Topics raised, discussions and ideas:

Total agreement between practitioners to map this area as a protection forest (total cover), the

necessity to include it in the HZM and to plan adapted measures to increase the protection function.

Propositions for mapping this forest

Blue reservation but not binding (A) – should advise the population but they are not obliged –

information

(A) 2 different plans

o map 1 : objectives of forest management (protection, production, etc) – mandatory

o map 2 : HZM – not mandatory – only when settlement is in design

Blue zone (CH) – protection forest ok – but not enough – danger is still there – In CH, forest

protection maps cover all land types (private, state, cantons) – the balance is ensured because of

the payment of owners – they have to follow forest protection guidelines

(T) forest management plan including measures to ensure the protection function – HZM

regulation is in project – risk plan also for other sectors (transport (railways and roads)) –

necessity to involve stakeholders from different sectors and administrations

How to manage in this case the authorisation to build houses or not?

Confer to Austria HZM – brown zone type – Rockfall/landslides danger indication (A) – need for an

external expertise to evaluate the Hazard and the risk for house building (owner is responsible to

develop protection works if needed) – the conclusion can also be that building is forbidden –

possibility to build protection works/structures – belonging to who ? – Who is responsible for

maintenance? New law – civil contract needed (Between the owner where the protection works

stand and the legal entity who build it – regulate property and ensure maintenance issues)

In terms of measures to increase the protection function, the following ideas were proposed:

Need to fence out the cattle and decrease the pressure of animal breeding in the lower part of the

forest (A)

Afforestation in the lower part to secure the protection function of the forest (A)

Not managing the forest is not the best way – increase the stability of the forest is needed (CH)

Increase awareness of the population – promotion of activities to ensure the protection role of

the forest (A)

Importance to take into consideration the history of the forest.

Global discussion: Decisions depend on the policy and the means – available instruments (funds,

legal framework, easy institutional framework).

Stop n° 2: Sixt Fer-à-cheval. “Marteloscope”

The situation:

Visit to a communal forest plot (n°30) located above a flat area, on the road side. Considering its location, this field could be chosen for future urbanisation. The forest does have a certain protection function, but the municipality is not prepared to finance a specific sylvicultural management if the investment does not allow any development at its foot. To secure the land from the rock fall hazard, the technical solution would be to complete the protection brought by the forest, by an earth dame built at the bottom. For the moment the French legislation does not allow building behind protection structures of any kind. Topics raised, discussions and ideas

Possibility of building new settlements in areas protected by protection structures

Stop n°3: Samoens. Settlement of “Vallon d’en Bas”.

The situation:

The municipality of Samoëns has a Natural Risk Plan since 1989. In this document, the extension of a blue zone (moderate level of avalanche hazard) above the village of “Vallon d’en Bas” was very criticized when it was published. The forest on the slopes above the village was considered by the inhabitants as a total protection against any new risk of avalanches (last event 1931). In February 1999, an avalanche reached the chapel of the village and the snow piled up to its roof, without crossing the road. The avalanche was triggered well above the forest line. An example of false security given to the population by the only presence of a forest. Topics raised, discussions and ideas

Taking historical events into account in HZM,

Influence of forest cover on HZM,

Stop n°4: Morzine. Settlement of “Tassonières”

The situation:

An ageing forest was identified as having a protection function above a line of nets for rockfall protection. An experimental site was set up within the framework of an Interreg project to rejuvenate the crop with the assistants of Austrian colleagues using the « Alpi » method.

The Mayor had been told that a good access was needed to insure a good maintenance of the nets and the forest. Nonetheless, the Mayor authorized a new building in the area needed for the access (moderate rockfall hazard zone – bleu zone). At the foot of the forest, other houses exist, in the same blue zone, but are not protected for the moment… the Mayor is thinking of putting up more nets, to protect the existing buildings but also maybe allow new constructions ! All of which will make the access to the forest and the nets even more difficult. Topics raised, discussions and ideas

The Mayor should not be the last one to decide the affectation of land in particular in the case of

land use planning/urban planning

This responsibility should not be put on someone who counts on his future election

Necessity of approval by the administration to build under protection works (in this case rockfall

net) (A) – possibility to oblige owners to put a protection in place, before building – range of

situations

Key points

Complexity of the regulation framework – in some countries – necessity to simplify in particular

for land use planning decision making

Stop n°5: Morzine. “Valley of slates”

(See “Field visit sheet: Morzine/La Tassonière; Valley of slates: la Daranse des Prodains; Rockfall

hazard.” Annex 9)

The situation:

On this site, the hazard of a rock collapse superior to 100 000 m3 is taken as reference for a 100 year return period. Taking such a hazard into account for HZM is unique in Haute-Savoie and has rarely been done in France. The forest here does not play any protection role. The question triggered by this stop, is how to take extreme phenomena into account in HZM.

Topics raised, discussions and ideas

Possibility of expropriation – red zone – funded by the state (CH (parts paid by the state/ in some

cases by the insurance (obligatory insurance of each house owner in most of the cantons that

covers you against natural hazard)) – F compensation of the losses – in (A) you cannot force

people to leave their houses

Philosophic question – solidarity law – owners vs non owners

Stop n°6: Morzine. “Valley of La Manche”

(See “Field visit sheet: Morzine/Manche Valley. La Dranse de la Manche. Rockfall hazard” annex 10)

The situation:

After the fall of a rock of 24m3, which stopped just behind a house, a methodology for the study and

mapping of the rockfall hazard (in french called MEZAP) was tested in this particular case.


Interesting methodology

Concerning Lidar covers – Exist on the totality of the territory for Austria and Switzerland (below

2000 m a.s.l.) – added value especially for torrent control

Quality of the lidar tool depending of the company in charge of the data collection

Interesting for landslide especially if you acquire time series (drone Vs flight)

In the future, tool to determine the protection function level of the forest (density, composition ,

stages and sanitary) Already used in Austria for this purpose

Site n°7 : Taninges. “Route de Rond”

The situation:

In February 1999, snowslides (slutch) started in a deciduous stand, above a high traffic road. The municipality suggested to replace these species by conifers, but the forests were private property. In 2011, the project for a clear cut was submitted to the departmental authorities. They asked the operator to follow the guidelines for sylviculture in mountainous areas (GSM): no blanks larger than 20 ares (or 50 m measured following the steepest slope). The use of a cable for extraction created an opening of more than 60 ares with a length of 120 m. It so happened that a rock was destabilized and hit a car, passing on the road. This has created a contentious issue which is still on going. Hazard mapping above roads has become a big issue In Haute-Savoie.


Worst example of protection forest management – just taking wood out – no consideration of the

protection function

In this case, measures have to be planned like cutting trees on this slope to increase protection

(Austrian method)

Importance of forest plans – legal force of the elaborated plans

Key points highlighted at the end of the workshop during the brainstorming

(A) Decision making process under political hands – laws and regulations cannot cover every case

– awareness raising of stakeholders and especially decision makers is needed

(CH) highlight of the importance of the institutional framework – the easy way of implementation

of Swiss regulations – existence of guidelines

(A) increase the interest of the participants to take the forest protection role into consideration

(T) interest in the different approaches of HZM – something new for Turkey – new tools – need for

a transfer of know-how / advices

(F) Importance to improve the communication between sectorial stakeholders (urban planners –

forest managers – hazard zone mappers)

(A) research has to be done to better assess the protection role of the forest for each type of

hazard

Geologic situation

Sixt-Fer-A-Cheval

Le Giffre

Rockslide near the Fer-à-Cheval circus

RTM service of Haute-Savoie

(74) department

Geographic and geologic situation

The Fer-à-Cheval circus is high touristic place

with easy access at the end of the Giffre valley.

It is a glacier circus which cuts all the

sedimentary deposits that are layed on a

granite base.

The Jurassic limestone layers (Dogger) produce

regularly massive rockfall of a volume between

some dm3 to more than 1 m3.

There has been also mass rockslides in the past

(June 1600 at the “Tête noire”, 9 March 1944

and 8 June 1974 for the “Corne du Chamois”).

Geographic situation

Study of the hazard and risk

A hazard map has been made in1987 with

methodologies and means available at that

time. The forest was not mapped.

In 2014, ONF forest management services asked

ONF RTM for the necessity to adapt the

management processes for a protection

purpose.

Protection measures

The adopted principle is to ensure sustainably

the protection function of the forest and the

dissipation of rockfall energy for rocks under 2

m3.

It has been approved to regenerate the forest

through the planting of forest openings with

deciduous tree species. ONF will present at the

end of this year the project to the municipality.

Other options include the erection of a dam of

protection for an average cost of 2k€/ml.

Notes – discussions

The forest is everywhere but was not taken into

account during the hazard mapping realised in 1987

for the PPR.

Geologic situation

Morzine / La Tassonière ; valley of slates

La Dranse des Prodains

Rockfall hazard


(74) department


Morzine municipal territory covers the

upstream of the Dranse valley in the pre-alpine

massif of Chablais. It is a touristic station

reputed and well frequented ( Avoriaz domain).

This station is composed by three valleys that

cuts thrust sheets of Chablais with a

“piemontaise” origin. One of this thrust sheet is

called breccia.

In fact, this geologic formation is composed by

two levels of breccia cutted by a slate level.

This slate layer has been exploited during two

centuries.

Due to this extraction, two kind of rockfall

hazard should be identified:

- Compact rockfall but isolated like under

every escarpment ;

- Rockslides of bigger volumes (more than

100 000 m3 (1873 et 2001) probably

caused by the collapse of old extraction

galleries.


Study of the hazard and FFP

Between 2009 and 2012, ONF managed an

Interreg project with the aim of mapping forest

with a function of protection (FFP) and

implement pilot sylvicultural measures after a

diagnosis.

The mapping consisted in the identification of

starting zones where rockfall or avalanche can

happen, the related automatic identification of

affected zones (energy line calculation process)

and then overlapping those maps with the limits

of the forest. The final step of the process was

the control of the hazard on the field and the

observation of the characteristic of the forests.

Protection measures

The cartography of the index of mastery of the

hazard (IMA = indice de maitrise de l’aléa in

French) by the forests permits to organise

priorities and to orientate sylviculture between

wood production and the improvement of the

protection role of the forest.

Rhône-Alpes region benefits of EU funding

opportunities (FEADER) to ensure sylvicultural

measures necessary to maintain or improve the

protection function of the forest.


Geologic situation

Morzine / Manche valley

La Dranse de La Manche

Rockfall hazard


(74) department


The municipality of Morzine is situated in Haut

Chablais and has a risk prevention plan (in

French: PPR) under implementation. At the time

where the revision of this important document

was almost finished, a rock of 24 m3 felt and

stopped just behind a housing. The concerned

zone was obviously described in the PPR as a

zone without any risk (risk assessed by an expert

without modelling/calculation = expert opinion).

After that event, it has been asked to RTM

service to study this phenomenon and the

concerned sector with added means.

The methodology of study and hazard mapping

P (in french called MEZAP) was tested in this

particular case. Before having afield approach,

we have identified at the office the potential

starting zones and reaching zones for different

energy lines. On the field, we have identified,

measured, dated in age classes and took pictures

of rocks at the foot of the slope every 50 meters.

At the office, we calculated an indicator of the

level of activity and an energy line and mapped

equal hazard zones. A local meeting permitted to

discuss the result of the study with the

population and confront their perception of the

risk.


Study of the hazard and risk

The view of this data under a GIS permitted to

propose a mapping of the P hazard that goes

further than the expert's opinion.

On this data, we add the forest area that can

play a protection role and dissipate partially the

energy of rockfalls.

Protection measures

The forest plays here a relative protection role.

It has been estimated that the forest is efficient

to protect against rocks that are not above 1m3.

However we integrated this new knowledge of

hazard P in the PPR, we strongly recommended

the municipality to build a dam to protect

against rockfall.

The PPR does not allow anymore to build

houses in this zone.


Country / province

Structure / Organisation

Responsabilities Concerned laws/regulations Mandatory

Scale

Average budget of expertise for HZM / hectares

Type of hazard tacking into

account in HZM and risk maps

Return period

Special type of zone in HZM for protection forest?

Update of HZM/risk map if new protection

works/devices implemented?

Possibility to built beneath protection works?

Type of hazard

a) General appreciation of the protection role of the

forest function of the type of hazard

b) Assessment of the protection role of forest during HZM

c) Qualitative and/or quantitative assessment

If assessment is done

d) Name of utilized tools/ Guidelines / standards

Since 1984, France has instaured NRPP - Envir onmental law of 1995 precised the content of

NRPPs.

RPPs are statutory documents, but not mandatory They are

established under the impulse of the Prefets (mandatory if it is

asked by the authority).

Avalanchesboth but in general more

positiveunsystematic

generaly qualitative but sometime quantitative

depending on the stakes

Qualitative: Mountain sylvicultural guidelines

Quantitative: xxxx

EU Floods directive (26/11/2007)

This directive was translated in french law by a decree, in 2011

(decree n° 2011-227 02/03/2011). It mainly concerns plains and

valleys but does not make any mention of the regulation role of the forests in the river catchment.

Rockfalls/rockslides positive unsystematicgeneraly qualitative but sometime quantitative



Quantitative: xxxx

Prefecture (Prefets, state authority at

departemental level). ONF RTM (State technical

support in departments with

RTM service)

Elaboration and validation of Hazard Zone Map and risk map

(Natural risk prevention plan (NRPP))

Shallow Landslidesboth but in general more

positivenever qualitative

Communes (Mayor)Integration of the risk map in

local land use planningTorrent Floods

both but in general more positive

unsystematicgeneraly qualitative but sometime quantitative



Quantitative: xxxx

Private engineering companies

Elaboration of the Hazard zone map and proposal of a NRPP

Debris flowboth but in general more





Quantitative: xxxx

Avalanches positivesystematic but not

mandatory



ONR 24 800 ff. (see example attached)

Rockfalls/rockslides positivesystematic but not

mandatoryqualitative


Local commission composed by 4

Persons:Member of the

FMAFEW,Member of provincial

administration,Mayor of the

commune,Head of the section

of the ASTAC

Integrate observations and comments in the HZM after a public consultation process of

stakeholders

Regulation from 30. July 1976 concerning hazard zone maps, “Hazard Zone Map Regulation”

(Federal Law Gazette No. 436/1976): For every community

with catchment areas of avalanches or torrents, there has to be established a HZM by the

local authority of the ASTAC.

Yes Shallow Landslides positive unsystematic qualitativeONR 24 800 ff. (see example

attached)

Regional site offices of the Federal

Ministry of Agriculture and Forestry within

their area of responsibility (FLG.

No. 507/1979)

Devising of hazard zone maps, priorizing and planning of measures according to their urgency

(HZM-Order from 30. July 1976, FLG. No. 436/1976)

Torrent Floodsboth but in general more

positivesystematic and

mandatory





Only technical support but no responsibility for the whole HZM


negativesystematic and

mandatory




Annex 11: Table of the institutional, legal and technical framework of HZM

Regulation from 30. July 1976, FLG. No. 436/1976

§ 6. c) the blue reservation areas

identify areas especially 1. for carrying out technical or forest-

biological measures of the departments and are necessary

to guarantee the function of these measures or 2. need a

special kind of management to guarantee the protective

function of a measure or the sheeting success.

Yes

Revision of the hazard zone map on the basis of changed

preconditions - continuous adaptation

Yes

HZM as a planning instrument and as the basis of land-use planning, building trade and

safety planning

Austria

Technical checking of the HZM after production of the first

draft

Validation and authorisation for implementation of the HZM

Federal ministry of FMAFEW

(BMLUFW)

Institutional context

France

Ministry in charge of environment and

sustainable development

(MEDDE)

Legal framework, technical guidelines and funding

Law/regulations for hazard mapping Protection role of forestProducts/Maps Land use planning

No

Protection devices and works are not taken into account for the

elaboration and revision of hazard maps and risk maps

No

It is forbidden to construct beneath protection works even dought the permission is often given by prefets at the demand

of mayors

1:10000 (HZM)1:5000 (risk

map/reglementary map)

12 - 15 euros/ha

All type of natural hazard

Return period considered for

HZM: 100 years

Since 2004, new colours in risks map - green colour to highlight the protection role played by forests - implementation of

adapted sylvicultural measures

Less than 20 NRPPs have taken into account forests with a

protection function.

The national guidelines for hazard mapping do not impose

to map the forests.

The forestry code recognizes PPRs (Article L144-1) and

highlights the possibility of PPRs to define management measures to maintain the protection role of

the forest

Federal Constitution Act 1920, defined Torrent control

(avalanches incl.) as a federal competence

Forest Act of 1975 introduced Hazard zone maps as part of the

design of hazard zone plans.

Yes

All type of natural hazard but legally-

binding only hazards caused by torrent and

avalanches

Violet reference areas identify

areas where the protection

function depends on the

preservation of the state of the

soil or the landscape.

Return period considered for

HZM: 150 years

Overview 1:50.000

Risk-Areas 1:10.000

Zones within villages 1:1.000

Guide lines from 04. February 2011 concerning making of hazard zone maps, (internal

regulation LE.3.3.3/0185-IV/5/2007, version 2011)

Yes

Confederation

Legal framework - technical guidelines - financing of

measures (50 % of the costs for hazard zone mapping are paid

by the Confederation)

Avalanchesboth but in general more




Qualitative: xxxxQuantitative: xxxx

CantonsRealise HZM and Regional master plans and finance

Rockfalls/rockslidesboth but in general more





MunicipalitiesLocal developement plans and land-use planning


positiveunsystematic qualitative






FOEN published in 1997 recommendations for hazard zone mapping and in 2015 an implementation aid for mass

movement

Yes Debris flowboth but in general more



Avalanches Positive unsystematic qualitative Not established

Rockfalls/rockslides Positive unsystematic qualitative Not established


positiveunsystematic qualitative Not established

Municipalities

Hazard zone maps production

Implementation in landuse planning & contingency plans

Torrent Floods both unsystematic qualitative Not established


Debris flow both unsystematic qualitative Not established

Turkish State Hydraulic Works

preparing flood hazard maps for the whole Turkey Avalanches

both but in general more positive

unsystematicgeneraly qualitative but sometime quantitative


OGM

preparing avalanche hazard maps for Çoruh River Basin but not zoning yet

Collecting data on independent events

Rockfalls/rockslidesboth but in general more



depending on the stakesQualitative: xxxx

Quantitative: xxxx





Quantitative: xxxx





Quantitative: xxxx





Quantitative: xxxx

Yes

Existing protection works are considered in hazard maps,

hazard maps has to be updated when new protection works are

built

Yes

It is mandatory to integrate the information of HZM in all spatial activities, in local developement

plans and land-use planning

Yes

- Taking into account positive effects of forest cover (similarly to protection structures) means

take on the responsabilty the keep this function effective on

the long term.

- Sudden radical changes in the forest cover conditions (due to

storms, avalanche) theoretically leads to a revision of hazard

maps

-

No

Protection forests are considered only in a qualitative manner based on expert knowledge.

Yes

Existing protection works are considered in hazard maps,

hazard maps has to be updated when new protection works are

built

Yes

It is mandatory to integrate the information of HZM in all spatial activities, in local developement

plans and land-use planning

No

In the provincial guidelines for Hazard Mapping the forest role is not explicitly defined, BUT forest

has to be considered in the whole hazard assessment

procedure (hydrologic analysis, scenario definition, hydraulic

analysis)

Protection forests are mapped

Autonomous Province of

Bolzano

All type of natural hazard

Danger level according to a

probability-intensity-diagram

(5 hazard zone types).

(level of probability

function of the return period)

Relevant laws and ordinances: Federal Act on Forest, Forest

Ordinance, Federal Act on Spatial Planning, Federal Act on Water Constructions (not conclusively)

Yes

Hazard zone mapping is more or less completed in Switzerland

Autonomus province of bolzano

HZM Financing (80%)

Methodology Definition for HZM

Structural measures design

Civil Protection function 2008 Provincial Guidelines for Hazard Mapping based on the „Swiss model“ and consistant

with the flood directive

Mandatory for all municipalities

Adaptations in order to respect italian legal framework

Hazard maps are not „legally binding“ for forest management

-

2008 – Landuse planning Law introduce Hazard & Risk Plans

Mandatory for all municipalities

All type of natural hazard (floods,

avalanches, mass movements)

Danger level according to a probability-

intensity-diagram (5 hazard zone

types).

(level of probability:

function of the return period or

the probability of occurrence)

1:2000 to 1:10000 (HZM),

more than 1:10000 (hazard index map)

The average budget of expertise is not determined

by the Confederation

Turkey Not applicable Not applicable Not applicableNo legal text on natural hazard

zone mappingNot applicable

Switzerland

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